Parathyroid Hormone (PTH) is the most important endocrine regulator of calcium and phosphorus concentration in extracellular fluid. Parathyroid Hormone (PTH) is secreted from cells of the parathyroid glands and finds Parathyroid Hormone's major target cells in bone and kidney. Like most other protein hormones, Parathyroid Hormone (PTH) is synthesized as a preprohormone. After intracellular processing, the mature hormone is packaged within the Golgi into secretory vesicles, the secreted into blood by exocytosis. Parathyroid Hormone (PTH) is secreted as a linear protein of 84 amino acids. Recombinant Human Parathyroid Hormone (PTH) produced in E. coli is a single, non-glycosylated, polypeptide chain containing 84 amino acids and having a molecular mass of 9,000 Da.